Voltage-gated calcium channel γ2 subunit gene is not deleted in velo-cardio-facial syndrome

Velo-cardio-facial syndrome (VCFS) has been associated with schizophrenic symptoms in some patients and is caused by a deletion of 22q11.21-q11.23.(1-4) The voltage-gated calcium channel (VGCC) gamma2 subunit is located on chromosome 22(5) and is telemeric to the most commonly observed VCFS deletion region but is near a putative marker for schizophrenia (D22S278).(6,7) Metaphase spreads of four controls, four patients with VCFS, and one patient with VCFS and schizophrenia were evaluated for the VCFS deletion using the VCFS-diagnostic probe, TUPLE 1, and for deletion of VGCC gamma2 subunit gene using probes for that gene's exon 1 and exons 3 and 4.(8) All Of the VCFS patients had deletion of the TUPLE 1 probe on one chromosome of the chromosome 22 pair. None showed deletion of the gamma2 subunit exons studied. The location of the gamma2 subunit gene at 22q13.1 was confirmed by FISH in all cases. This study did not show a deletion of the gamma2 subunit gene as a distinguishing feature of our patient with VCFS and schizophrenia.